• 한국재료학회지
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• 제28권1호
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• pp.6-11
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• 2018

There are various manufacturing processes for pure $SiO_2$ that is used as abrasives, chemicals, filters, and glasses, and in metallurgy and optical industries. In the optical fiber industry, to produce $SiO_2$ preform, $SiCl_4$ is utilized as a raw material. However, the combustion reaction of $SiCl_4$ has caused critical environmental issues, such as ozone deficiency by chlorine compounds, the greenhouse effect by carbon dioxide and corrosive gas such as hydrochloric acid. Thus, finding an alternative source that does not have those environmental issues is important for the future. Octamethylcyclotetrasiloxane (OMCTS or D4) as a chlorine free source is recently promising candidate for the $SiO_2$ preform formation. In this study, we first conducted a vaporizer design to vaporize the OMCTS. The vaporizer for the OMCTS vaporization was produced on the basis of the results of the vaporizer design. The size of the primary particle of the $SiO_2$ formed by OMCTS was less than 100 nm. X-ray diffraction patterns of the $SiO_2$ indicated an amorphous phase. Fourier-transform infrared spectroscopy analysis revealed the Si-O-Si bond without the -OH group.

• 한국대기환경학회지
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• 제20권6호
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• pp.749-758
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• 2004

Nitrous oxide ($N_2$O) has been known as an important trace gas due to the greenhouse gas and the major source of stratospheric oxide of nitrogen (NO). Soil is the major source of $N_2$O in nature. The physicochemical characteristics of soils affect the emission of $N_2$O from soil. These physicochemical parameters are soil moisture, soil temperature, and soil N content. Since these parameters are correlated to the flux of $N_2$O from soil individually and compositely, there still remain many unknowns in the mechanism to produce $N_2$O in soil and the roles of such physicochemical parameters which affect the soil $N_2$O emission. Soil $N_2$O fluxes were measured at different levels in water filled pore space (WFPS), soil temperature and soil N contents from the same amounts of soils which were sampled from agriculturally managed upland field in a depth of ～30 cm at Kunsan. The soil $N_2$O flux measurements were conducted in a laboratory with a closed flux chamber system. The optimum soil moisture and soil temperature were observed at 60% of WFPS and ～13$^{\circ}C$. The soil $N_2$O flux increased as soil N contents increases during the whole experimental hours (up to 48 hours). However, average $N_2$O flux decreased after ～30 hours when organic carbon was mixed with nitrogen in the sample soils. It is suggested that organic carbon could be important for the emission of $N_2$O, and that the ratio of N to C needs to be identified in the process of $N_2$O soil emission.

• Plant Biotechnology Reports
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• 제3권4호
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• pp.277-283
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• 2009

One of the limitations to conducting maize Agrobacterium-mediated transformation using explants of immature zygotic embryos routinely is the availability of the explants. To produce immature embryos routinely and continuously requires a well-equipped greenhouse and laborious artificial pollination. To overcome this limitation, an Agrobacterium-mediated transformation system using explants of type II embryogenic calli was developed. Once the type II embryogenic calli are produced, they can be subcultured and/or proliferated conveniently. The objectives of this study were to demonstrate a stable Agrobacterium-mediated transformation of maize using explants of type II embryonic calli and to evaluate the efficiency of the protocol in order to develop herbicide-resistant maize. The type II embryogenic calli were inoculated with Agrobacterium tumefaciens strain C58C1 carrying binary vector pTF102, and then were subsequently cultured on the following media: co-cultivation medium for 1 day, delay medium for 7 days, selection medium for $4{\times}14$ days, regeneration medium, and finally on germination medium. The T-DNA of the vector carried two cassettes (Ubi promoter-EPSPs ORF-nos and 35S promoter-bar ORF-nos). The EPSPs conferred resistance to glyphosate and bar conferred resistance to phosphinothricin. The confirmation of stable transformation and the efficiency of transformation was based on the resistance to phosphinothricin indicated by the growth of putative transgenic calli on selection medium amended with $4mg\;1^{-1}$ phosphinothricin, northern blot analysis of bar gene, and leaf painting assay for detection of bar gene-based herbicide resistance. Northern blot analysis and leaf painting assay confirmed the expression of bar transgenes in the $R_1$ generation. The average transformation efficiency was 0.60%. Based on northern blot analysis and leaf painting assay, line 31 was selected as an elite line of maize resistant to herbicide.

• 한국토양비료학회지
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• 제48권6호
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• pp.582-587
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• 2015

This study was conducted to compare the plant growth and fruit quality of blueberries grown in different soil textures of Korea, in order to utilize the results for stable production and soil improvement. Rabbiteye blueberry cultivars 'Tifblue' and 'Baldwin' were planted and grown for three years from 2013 in wagner pot (1 $2000a^{-1}$) in a greenhouse of Namhae Sub-station, Institute of Horticultural and Herbal Science. The plants were grown in four soil textures, sand, sandy loam, loam and silt loam, and nutrient uptake and growth characteristics of plants were investigated. Leaf nitrogen and phosphorus contents of two cultivars grown in different soil textures ranged between 8.6 to $10.5gkg^{-1}$, which was lower than appropriate level for rabbiteye blueberry. However, the contents of potassium, calcium and magnesium in leaves were appropriate levels as $2.29{\sim}3.62gkg^{-1}$, $4.46{\sim}5.46gkg^{-1}$ and $1.45{\sim}2.12gkg^{-1}$, respectively. Nitrogen and phosphate contents in leaves were higher in the two cultivars grown in silt loam soil. There was no significant difference in plant volume and root dry weight among four soil textures in two cultivars. However, dry weight of leaves and branches were highest in loam soil. Fruit production was highest in loam and silt loam soil in two cultivars, showing negative correlation with the amount of sand in soil. However, sugar and acidity showed no correlation with sand content in soil. These results show the limit to the blueberry growth in soil that has no nutrient holding capacity; however, most of Korean soils that have good nutrient holding capacity can produce competitive fruits if the drainage is improved.

• 멤브레인
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• 제31권2호
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• pp.133-144
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• 2021

알칼리 수전해 시스템은 다양한 수소 생산 공정 중에서 가장 온실가스 발생량이 적은 그린 수소를 생산하는 방식 중 가장 오래된 기술이다. 알칼리 수전해 시스템은 알칼리 조건에서 사용되며, 고분자 전해질막 수전해와는 다르게 니켈, 코발트, 은 등의 안정한 전이금속을 전극촉매로 사용할 수 있다. 이 시스템은 가격이 저렴하고 대용량화가 용이하다는 장점을 가지고 있다. 이러한 장점으로 알칼리 수전해 시스템은 20세기 초부터 MW급 수소발생장치에 적용되어 왔으며 현재 20여 개의 제조업체에서 상용제품을 판매하고 있는 안정화된 기술이다. 본 논문에서는 알칼라인 수전해의 기본원리 및 사용되는 촉매, 전극, 격막 등에 대해 알아보고 그 중 핵심소재인 격막의 연구개발 동향에 대해 살펴보고자 한다.

• 한국물환경학회지
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• 제37권2호
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• pp.128-136
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• 2021

It is generally known that a wastewater treatment plant (WWTP) consumes immense energy even if it can produce energy. With an aim to increase the energy independence rate of WWTP from 3.5% in 2010 to 50% in 2030, the Korean government has invested enormous research funds. In this study, cost-effective operating alternatives were investigated by analyzing the energy efficiency and economic feasibility for biogas and power generation using new and renewable energy. Based on the US EPA Energy Conservation Measures and Korea ESCO projects, energy production and independence rate were also analyzed. The main energy consumption equipment in WWTP is the blower for aeration, discharge pump for effluent, and pump for influent. Considering the processes of WWTP, the specific energy consumption rate of the process using media and MBR was the lowest (0.549 kWh/㎥) and the highest (1.427 kWh/㎥), respectively. Energy-saving by enhancing anaerobic digester efficiency was turned out to be efficient when in conjunction with stable wastewater treatment. The result of economic analysis (B/C ratio) was 2.5 for digestive gas power generation, 0.86 for small hydropower, 0.49 for solar energy, and 0.15 for wind energy, respectively. Furthermore, it was observed that the energy independence rate could be enhanced by installing energy production facilities such as solar and small hydropower and reducing energy consumption via the replacement of high-efficiency operating.

• 한국기후변화학회지
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• 제5권3호
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• pp.189-197
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• 2014

Carbon footprint of apple was a sum of $CO_2$ emission in the step of manufacturing waste of agri-materials, and greenhouse gas emission during apple cultivation. Input amount of agri-materials was calculated on 2007 Income reference of Apple by Rural Development Administration. Emission factor of each agri- materials was based on domestic data and Ecoinvent data. $N_2O$ emission factor was based on 1996 IPCC guideline. Carbon dioxide was emitted 0.64 kg $CO_2$ to produce 1 kg apple fruit, and carbon dioxide was emitted 43.6% in the step of the manufacturing byproduct fertilizer, 1.3% in the step of the manufacturing single fertilizer, 4.7% in the step of the manufacturing composite fertilizer, 6.3% in the step of the manufacturing agri-chemicals, 14.6% in the step of the manufacturing fuel, 11.5% in the step of the fuel combustion, 17.7% of $N_2O$ emission by nitrogen application and 0.18% of disposal of agri-materials. It is needed for farmers to use fertilization recommendation based on soil testing (soil. rda.go.kr) because scientific fertilization is a major tools to reduce carbon dioxide of apple production. The fertilization recommendation could be also basic data in Measurable-ReporTablele-Verifiable (MRV) system for carbon footprint.

• Journal of Microbiology and Biotechnology
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• 제29권1호
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• pp.66-78
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• 2019

In this study, strain KNU17Pc1 was tested for its antifungal activity against Rhizoctonia solani AG-1(IA), which causes banded leaf and sheath blight (BLSB) of maize. KNU17Pc1 was tested further for its broad-spectrum antifungal activity and in vitro plant growth promoting (PGP) traits. In addition, the in vivo effects of KNU17Pc1 on reduction of BLSB severity and seedling growth promotion of two maize cultivars under greenhouse conditions were investigated. On the basis of multilocus sequence analysis (MLSA), KNU17Pc1 was confirmed as P. chlororaphis subsp. aurantiaca. The study revealed that KNU17Pc1 had strong in vitro antifungal activity and was effective toward all in vitro PGP traits except phosphate solubilization. In this study, for the first time, a strain of P. chlororaphis against Colletotrichum dematium, Colletotrichum gloeosporioides, Fusarium oxysporum f.sp. melonis, Fusarium subglutinans and Stemphylium lycopersici has been reported. Further biochemical studies showed that KNU17Pc1 was able to produce both types of phenazine derivatives, PCA and 2-OH-PCA. In addition, solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis identified 13 volatile organic compounds (VOCs) in the TSB culture of KNU17Pc1, 1-undecene being the most abundant volatile. Moreover, for the first time, Octamethylcyclotetrasiloxan (D4), dimethyl disulfide, 2-methyl-1,3-butadiene and 1-undecene were detected in P. chlororaphis. Furthermore, this study reported for the first time the effectiveness of P. chlororaphis to control BLSB of maize. Hence, further studies are necessary to test the effectiveness of KNU17Pc1 under different environmental conditions so that it can be exploited further for biocontrol and plant growth promotion.

• 공업화학
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• 제22권1호
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• pp.31-36
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• 2011

사불화탄소($CF_4$)는 반도체 제조공정에서 플라즈마 에칭과 화학기상증착(CVD)에서 사용되어온 가스이다. $CF_4$는 적외선을 강하게 흡수하고 대기 중 잔류시간이 길어서 지구온난화에 영향을 미치기 때문에 고효율의 분해가 필요하다. 본 연구에서는 플라즈마와 워터젯을 결합하여 방전영역을 증가시키고 다량의 OH 라디칼을 생성시켜 $CF_4$를 고효율로 분해할 수 있는 워터젯 글라이딩 아크 플라즈마 시스템을 개발하였다. 실험 변수로 전극 형태, 전극 각도, 가스 노즐직경, 전극 간격과 전극 길이를 취하였다. 변수실험을 통하여 Arc 형태의 전극에서 전극 각도가 $20^{\circ}$, 가스 노즐 직경이 3 mm, 전극 간격이 3 mm, 전극 길이가 120 mm일 때 $CF_4$ 분해율은 최고 93.4%까지 도달하였다.

• Journal of Plant Biotechnology
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• 제48권1호
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• pp.54-61
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• 2021

This work describe an efficient method for the shoot induction and plant regeneration of seedling-derived apical bud explants of Tilia mandshurica Rupr. & Maxim. The highest rate of shoot induction (82.2%) was obtained when apical bud explants from juvenile seedlings (5 months old) were cultured on Murashige and Skoog (MS) medium containing 1.0 mg/L 6-benzylaminopurine (BAP). However, apical bud explants obtained from mature trees (12 years old) did not produce any shoots, even with BAP supplementation. Among the three cytokinins tested for shoot multiplication (BAP, zeatin, and kinetin), BAP was the most effective; the highest number of shoots per explant (2.1) was observed on MS medium supplemented with 1.0 mg/L BAP. In contrast, the longest average shoot length (3.0 cm) was observed after growth on MS medium with 2.0 mg/L zeatin. No multiplication occurred when apical bud explants were cultured with kinetin-supplemented media. During rooting of in vitro-elongated shoots, the highest rooting rate (100%) was observed in half-strength MS medium supplemented with 0.5 ~ 1.0 mg/L indole-3-butyric acid (IBA) or 3.0 mg/L 1-naphthaleneacetic acid (NAA). During the acclimatization process, plantlets that were rooted on the IBA (0.5 mg/L)-supplemented medium had the highest survival rate (100%) and maximum root length (18.5 cm). These findings suggest that a low concentration (0.5 mg/L) of IBA is appropriate for the rooting and acclimatization of T. mandshurica. Plants were successfully transferred to the greenhouse with a 100% survival rate. This protocol will be useful for the large-scale propagation of Tilia species.